Check your .htaccess file for instructions like "deny from" or RewriteRule that ends in [-F]. This is where most 403 errors come from, but it's impossible to know for sure without examining your system.
ok.. i will assume that during development your project runs on your localhost to troubleshoot this, first check your apache if the mod_rewrite rule is on (this is important because this extension enables the usage of your .htaccess)